The present invention relates to a method and apparatus for monitoring the crimp quality of a synthetic filament yarn produced by false twist texturing process.
A method of monitoring the tension of a yarn advancing between the false twisting unit and the delivery system in the texturing zone of a multi-position false twist crimping machine, in which a mean value signal is continuously formed, is known from U.S. Pat. No. 4,720,702 to Martens. In that known method, use is made of the fact that the yarn tension between the false twisting unit and the delivery system of the texturing zone allows essential conclusions to be drawn as to the control of the process during the texturing and the quality of the yarn produced. More particularly, the yarn tension is monitored such that, on the one hand, the minimum and maximum values of the tension do not leave a certain range on either side of the continuously determined mean value, and such that, on the other hand, the continuously determined mean value of the yarn tension does not leave a certain predetermined range.
It is an object of the present invention to monitor the intensity and uniformity of the twisting process in the texturizing zone and also to monitor and record the uniformity of the setting of the twist attained in the advancing yarn by a thermal setting process, these parameters directly reflecting the results of the texturing process.